function ret=calculate_joinlink(reliability,path_link)
len=length(path_link);
ret=1;
join_link=[];
if len==1
    ret=power(reliability(end),length(path_link{1}));
else
    for i=1:len
        join_link=union(path_link{i},join_link);
    end
    ret=power(reliability(end),length(join_link));
end
